You may want to get into contact with daplunk and check out the github wiki:
https://github.com/Sklore/HL_DD_5e_Colab/wiki
I don't think there's a real style guide on how to break down race versus backgrounds but once you look at how the community files get broken down you can see a general pattern to the how the files are named.
COM_5ePack_XXX-YYYYYYY.user
XXX is a three letter code that *someone* working in the community assigns to the source. Like COS = Curse Of Strahd. This same three letter code is often given to the "source" ID in the .1st files for new sources.
YYYYYY is the section you've worked on. If you are doing or have decided to do all the backgrounds you might just show it by typing backgrounds...
It also depends on the source - some sources like the PHB are broken up into multiple tasks so many can work on it at once. Others like the UA articles are just one file for everything.